Skiagraph



(No Model.)

J. M. MAXWELL.

SKIAGRAPHI. No. 356,144. Patented Jan. 18, 1887. v

UNITED STATES JOHN M. MAXWELL, OF CHICAGO, ILLINOIS.

PATENT OFFICE.

SKIAGRAPH.

SPECIFICATION forming part of Letters Patent No. 3 6, t d u y 8 Application filed May 17, 1886. Serial No. 202,488. (No model.)

To all whom it may concern:

. Be it known that I, JOHN M. hIAXWELL, a citizen of the United States, residing at Chicage, in the county of Cook and State of Illinois, have invented certain new and useful Improvements in Skiagraphs, of which the following is a specification.

My invention relates to devices for copying or duplicating pictures or natural objects; and its obj eet is to provide a device whereby such pictures or objects may be projected upon a drawing-surface over which the hand of the operator can freely pass, while at the same time he sees the picture T as it appears projected and the instrument which is copying it.

This device I have called a skiagraph, or shad ow-writer, and it isillustrated in the accompanying drawings, wherein Figure 1 is a perspective of my device without a reflector. Fig. 2 is the same with a reflector. Fig. 3 is a detail of the drawing-board. Fig. 4 is a detail of the transparent medium. Fig. 5 is adetail of the reflector. Fig. 6 is a detail of the reflector-supports. Fig. 7 is a detail of the objectsupport used with the reflector. Fig. 8 is a detail of the transparent-medium supports.

Like parts are designated by the same letter in all the figures.

A is a common drawing-board; B B, vertical grooved posts thereon, held in place by the holes I I. C is an object-support,held erect on the board by means of a peg thereon and the hole J. D is a transparent medium,the su rface of which reflects while at the same time light passes through it. It is supported by the posts B B. E is a reflector, supported at an angle on the board by the wedges H H, held in place by the pegs thereon and the holes K.

-F is the drawing to be reproduced. G is the projection thereof. It will be understood that, these parts can be greatly varied as to size,

material, and angles at which they set.

The use and operation of my invention are as follows: The drawing is fastened to the strument is carried over the board along the V apparent projected lines of the picture, a reversed copy thereof will be drawn on the op posite side of the medium. The eye, in look ing at the surface of the medium, will see the reflected picture and also the lines made on the board or the hand and instrul'nent which makes them. In the figure the hand and pencil are shown as seen in part through the medium as the picture is about to be completed. This picture is, as shown, reversed. If it is desired to makea direct picture, the mirror is used, as in Fig. 2. Here the object or picture is placed erect on the board, as at C. From this point it passes through the medium and forms an image on the reflector. This image now occupies the position of the picture in the original, Fig. 1, and this image is reflected from the surface of the medium as the drawing itself was in Fig. 1. This projected drawing is direct, however, as it is reversed twiceonce on the mirror and once on the surface of the medium.

The parts and their operation can be greatly varied by varying the angles at which they set. There must, however, be a transparent medium from which the reflected picture appears as if projected andthrough which the tracing-instrument can be seen in operation.

I claim and desire to secure by Letters Patent 1. The combination of a drawing-board having perforations on opposite sides with two posts, each adapted to be inserted into one of said apertures and each provided with a 1ongitudinal groove, and a plate of glass of such size as to be received into the grooves of the posts set up on the board.

2. The combination of the board A with the transparent mediums D and C and the reflector E. p

3. In a skiagraph, the combination of a pictureholder, a drawing'board, a transparent JOHN IvI. MAXWELL.

\Vitnesses:

F. W. PARKER, G. C. JACKSON.

IOO 

